Do not export the DISPLAY varialble and no longer gives that error, but the remote machine (vector linux) that I am from ubuntu using ssh-X shiva@10.1.1.113 run xclock and is done in the same in a process that is with ps-e, but if I run firefox & it runs on the local machine (Ubuntu) because I realize this is in Spanish and one in English. You seem to run randomly because sometimes running firefox from the remote. Any ideas ?. What am I doing wrong???